Ejaculation is a Good Way to Ward Off Prostate Cancer

A study on ejaculation and prostate cancer risk, which made a big splash at last year’s annual meeting of the American Urological Association (AUA), was published online March 29 inEuropean Urology.

The publication provides greater detail on the main finding: that men might be able to lower their risk for prostate cancer by ejaculating frequently.

“This large prospective study provides the strongest evidence to date of a beneficial role of ejaculation in prevention of prostate cancer,” write the researchers, led by Jennifer Rider, ScD, MPH, a cancer epidemiologist at the Boston University School of Public Health.

However, another expert threw the requisite cold water on any firm conclusion.

“Association does not mean causation, so one has to be cautious about interpretation,” Janet Stanford, PhD, MPH, a prostate cancer researcher at the Fred Hutchison Cancer Research Center in Seattle, who was not involved in the study, said about the observational data.

The data come from 31,925 men in the prospective Health Professionals Follow-up Study, who were followed from 1992 to 2010. The average age of the men in 1992 was about 59 years.

During the 18-year follow-up, 3839 men were diagnosed with prostate cancer, and 384 of those cases were lethal.

In a 1992 questionnaire, men were asked to report their average monthly ejaculation frequency during three periods: age 20 to 29 years, age 40 to 49 years, and the previous year.

Association does not mean causation.

After potential confounders were controlled for in multivariate analyses, the relative risk for prostate cancer was about 20% lower in men who ejaculated at least 21 times a month than in men who ejaculated four to seven times a month. For high-frequency ejaculators, this risk reduction was seen in all three time periods (P trend < .0001 for all).

After the results were first reported at the AUA meeting, the study received a lot of mainstream news coverage, Dr Rider noted. But in some of the reporting, the emphasis was on the men who ejaculated at least 21 times per month, she explained.

It is true that risk reduction was more pronounced in high-frequency ejaculators than in lower-frequency ejaculators, she acknowledged. (Too few men reported zero to three ejaculations per month, so those reporting four to seven ejaculations per month served as the reference group.)

However, there was a significant relative risk reduction of 10% in men who reported eight to 12 ejaculations per month at 40 to 49 years, and of 20% in men who reported 13 to 20 ejaculations at 40 to 49 years (P trend < .0001).

In an interview with Medscape Medical News last year, Dr Rider warned against overemphasizing the high-end numbers.